A. Field of the Invention
The present invention relates to the field of network communications, and more particularly to cable modem network management.
B. Background of the Invention
Cable television networks such as those provided by Comcast Cable Communications, Inc., of Philadelphia, Pa., Cox Communications of Atlanta Ga., Tele-Communications, Inc., of Englewood Colo., Time-Warner Cable, of Marietta Ga., Continental Cablevision, Inc., of Boston Mass., and others provide cable television services to a large number of subscribers over a large geographical area. The cable television networks typically are interconnected by cables such as coaxial cables or a Hybrid Fiber/Coaxial (xe2x80x9cHFCxe2x80x9d) cable system which have data rates of about 10 Mega-bits-per-second (xe2x80x9cMbpsxe2x80x9d) to 30+ Mbps.
The Internet, a world-wide-network of interconnected computers, provides multi-media content including audio, video, graphics and text that require a large bandwidth for downloading and viewing. Most Internet Service Providers (xe2x80x9cISPsxe2x80x9d) allow customers to connect to the Internet via a serial telephone line from a Public Switched Telephone Network (xe2x80x9cPSTNxe2x80x9d) at data rates including 14,400 bps, 28,800 bps, 33,600 bps, 56,000 bps and others that are much slower than the about 10 Mbps to 30+ Mbps available on a coaxial cable or HFC cable system on a cable television network.
With the explosive growth of the Internet, many customers have desired to use the larger bandwidth of a cable television network to connect to the Internet and other computer networks. Cable modems, such as those provided by 3Com Corporation of Santa Clara, Calif., Motorola Corporation of Arlington Heights, Ill., Hewlett-Packard Co. of Palo Alto, Calif., Bay Networks of Santa Clara, Calif., Scientific-Atlanta, of Norcross, Ga. and others offer customers higher-speed connectivity to the Internet, an intranet, Local Area Networks (xe2x80x9cLANsxe2x80x9d) and other computer networks via cable television networks. These cable modems currently support a data connection to the Internet and other computer networks via a cable television network with a data rate of up to 30+ Mbps which is a much larger data rate than can be supported by a modem used over a serial telephone line.
However, most cable television networks provide only unidirectional cable systems, supporting only a xe2x80x9cdownstreamxe2x80x9d data path. A downstream data path is the flow of data from a cable system xe2x80x9cheadendxe2x80x9d to a customer. A cable system headend is a central location in the cable television network that is responsible for sending cable signals in the downstream direction. A return data path via a telephone network, such as a public switched telephone network provided by ATandT and others, (i.e., a xe2x80x9ctelephony returnxe2x80x9d) is typically used for an xe2x80x9cupstreamxe2x80x9d data path. An upstream data path is the flow of data from the customer back to the cable system headend. A cable television system with an upstream connection to a telephony network is called a xe2x80x9cdata-over-cable system with telephony return.xe2x80x9d
An exemplary data-over-cable system with telephony return includes customer premise equipment (e.g., a customer computer), a cable modem, a cable modem termination system, a cable television network, a public switched telephone network, a telephony remote access concentrator and a data network (e.g., the Internet). The cable modem termination system and the telephony remote access concentrator together are called a xe2x80x9ctelephony return termination system.xe2x80x9d
The cable modem termination system receives data packets from the data network and transmits them downstream via the cable television network to a cable modem attached to the customer premise equipment. The customer premise equipment sends response data packets to the cable modem, which sends response data packets upstream via public switched telephone network to the telephony remote access concentrator, which sends the response data packets back to the appropriate host on the data network.
When a cable modem used in the data-over-cable system with telephony return is initialized, a connection is made to both the cable modem termination system via the cable network and to the telephony remote access concentrator via the public switched telephone network. As a cable modem is initialized, it will initialize one or more downstream channels (i.e., downstream connections) to the cable modem termination system via the cable network or the telephony remote access concentrator via the public switched telephone network.
As a cable modem is initialized in a data-over-cable system, it registers with a cable modem termination system to allow the cable modem to receive data over a cable television connection and from a data network (e.g., the Internet or an Intranet). The cable modem forwards configuration information it receives in a configuration file during initialization to the cable modem termination system as part of a registration request message.
The cable modem termination system may initialize a large number of cable modems over a selected portion of the bandwidth. A cable system may use several cable modem termination systems connected to a large number of cable modems to provide service over a larger portion of the bandwidth. A cable system may be connected to as many as tens of thousands of cable modems.
During initialization, each cable modem scans for available channels. Typically, the cable modems scan the channels on the network sequentially starting from one end of the spectrum. Cable modems may also scan the network randomly. Once the cable modems are initialized, the usage of the spectrum may end up unbalanced with many cable modems locked on the same channel or a few channels that are near each other on the spectrum.
The imbalance may degrade system throughput. A small number of data channels carries the majority of the communications traffic while other channels are under-used. A cable system administrator may prefer to keep channel usage balanced across the spectrum. During operation, each cable modem may be moved to a different channel. The cable modem termination system may change the configuration file for the cable modem to be moved to initialize on a specific channel. The cable modem may then be restarted to force the cable modem to initialize on the designated channel. One problem with this method is that it is inefficient. The potentially high number of cable modems that may be connected to a cable system makes the process of changing the channel on individual modems tedious. The administrator may have to individually move a great number of modems to effect any noticeable improvement in the balancing of the load on the cable modem termination systems.
It would be desirable to be able to efficiently adjust the balance of channel usage in a cable system.
In view of the above, one aspect of the present invention is directed to a system for managing a network. The system includes a plurality of network devices connected to the network. The network devices are addressable as clusters of network devices by a multicast address. A plurality of data channels is provided. Each data channel is operable to provide communications to at least one of the plurality of network devices. The network devices are connected to a server for monitoring the data channel on which each of the first network devices are communicating. The server can also assign the network devices in a selected cluster to a selected data channel.
The server may also be used to determine if the network is unbalanced by the use of only one or a few of the data channels for communication. The server can then be used to move the network devices to different data channels in clusters to achieve a balanced network efficiently.
In a further aspect of the present invention, a method for managing a network is provided. A plurality of network devices is provided for communicating on a plurality of data channels. A network administrator is provided for issuing commands to the network devices. Each network device on the network is registered by assigning the network devices to a plurality of clusters of network devices and by assigning a multicast address to each the network device in each the cluster. A move command is sent to one of the multicast addresses to move the network devices in the cluster addressed by the one of the multicast addresses to a selected data channel.
The network administrator may be used to monitor channel usage to identify when the cable network has become unbalanced. The network may become unbalanced when only one or a few data channels are being used by the network devices. The network administrator may then send the move command to move the cluster or clusters to achieve a more balanced network.
The foregoing and other features and advantages of a preferred embodiment of the present invention will be more readily apparent from the following detailed description, which proceeds with references to the accompanying drawings.